Seal for rotary kilns



Nov. 16, 1943. J. B. WHITNEY 2,334,663

SEAL FOR ROTARY KILNS -Filed Jan. 24, 1941 I Y l0 l 2 o J4 Ja/W 144717715X- INV ENT OR'.

Patented Nov. 16,1943

SEAL Fon norms' mLNs John Boardman whitney, Highland ruk, N. s., assignor to National Lead Company, New York, N. Y., a corporation of New Jersey Application Jsnusryu, 1941, serial No. 375,760

z claims. (ci. 285-9) The present invention relates to rotary kilns, or furnaces, and has special reference to an lmproved seal for preventing the escape of dust and gases between the rotating and stationary surfaces of such furnaces.

Rotary furnaces, as is known, consist essentially of. a hollow rotatable drum or shell having at-one end a stationary combustion chamber and at the other a stationary stack hood. It will be appreciated that the prevention of the escape of dust and fumes between the stationary and movingsurfaces constitutes a problem in the operation of such furnaces. Prior to the present invention,` rotary furnaces have been equipped with elaborate and ,expensive sealing devices designed to overcome this problem. 'Such devices consisted of a metal ring fixed upon and moving with the rotary shell in contact with a second stationary metal e ring ilxed to a stationary part of the furnace.

Thus, the seal was effected by acontact of metal the rotatable shell without touching thesurface.

These are positioned in a plane at right angles to the horizontal axis of the shell. Between these two rings I5 and I6 there is provided a packing of suitable material Il, which contacts the rotary shell. A These rings and the packing between them are bolted by means' of bolts Into a flange i9, rigidly attached to the stationary end member.

Thisflage I9 may be, as shownin, Fig. l, an integral part of thestationary membercr, if desired, it may be in the forinofv a separate piece affixed, as by welding, to the stationary member. Preferably a gasket I 8 should be provided between `theflange I9 and therlng I6.

The embodimentshown in Fig. 2 differs from that shown in Fig. 1 in that .the ange 2 I -is ailixed to the rotatable' shell rather than the stationary member. Inthis embodiment the seal rotates with the shell in close contact with the surface of upon metal with resultant wear and consequent rapid and considerable escape of dust and fumes Y through the sealing device. Maintenance costs for such devices were naturally high v:and moreover, the escape of hot gases and dust represented .a loss of heat and the friction developed between the metal surfacesof the sealing devices necessi-A tated added power consumption. The present invention constitutes 4a simple and economical means ,for overcoming the disadvantages inherent in the seal devices of the prior art.

Fig. l; which represents a preferred embodiproved seal of the present invention. A portion of the rotating shell and the seal has been cutaway to present a crosssectional view. Fig. 2 is a representation of a second embodiment of the invention. Reference numeral il (Figs. 1 and 2) is the hollow rotatable shell of 'a rotary kiln provided with a geared ringil (Fig. 1) rigidly fixed around the circumference of the shell. The shell is rotated by means of the motor i l.a (Fig. 1), equipped with a geared drive wheel engaging the geared ring il (Fig. i). The shell is also provided with a bearing ringII-(Fig. l)

which rides upon support bearings Il (Fig. 1). Reference numeral IVI (Figs. -l and 2) represents onefof the stationary ends of the kiln. This may be either the combustion chamber or the stack houdend. Itwillbeseenthatinoperationthe snennrotsswahmthsstsusnsrypartu.

The preferred embodiment ofthe present in-v ventlcnasshowninFlsJconsistsofapairofnat 'ment of the present invention, is aside elevation 'of one end of a rotary kiln provided with an imthe stationary member and the packing material contacts the stationary'gend member.

The packing should be a material suitable to withstand the conditionsl under which the kiln is operated. For instance, where the kiln is operated at high temperatures and the dust and gases which are developed are of a corrosive nature, the

packing should be both heatand corrosion-resistant. The contact surface of the packing, in

order most effectively to constitute a seal, ought not to be-flat but rather made of individual strands, `or bristles, which have a brushing action when the shell rotates. For this purpose, such materials as mineral wool, glass wool and asbestos fibers are *especiany mutable: These materiels are, at the same time, heatand corrosion-resistant. It wlllbe seen, therefore, when such materials are employed in the present invention the brousmaterial's should be Placed between the rings 'so that the length of the ilbers is at right angles to the horizontal axis ofthe shell.

As the contacting surface of the packing wears Y away as is evidenced by the escape of gas and fumes the seal is tightened by the simple expedient of taking up on the bolts. `When theA packing is ilnallyused upit may be renewed by merely removing one orfboth rings and insertingv a newpacking. f

The -simple construction, ease of renewaL and enlcient operational? the improved seals contribute to maklng the'present inventions decided l advanceover prior artseals. It will beunderstood thattliepreseni:inventionisnottobelimitadasl mstruemralsembuttmsemsybewdmeam anycc'nvmientordesiredmannerwithoutdeparb. this! or circular mates II andi-.whichencircle ing from the scope ot the invention., In

as will be seen, the invention, in its broadest asmember of a rotating kiln for holding a packing material in close contact with the other member to effect a seal against the escape of fumes and dust.

I claimz,

1. An improved seal for rotary kilns comprising a pair of ilat rings encircling the rotatable part of said kiln at right angles t0 the axis thereof but providing clearance between the rotatable and stationary parts of said kiln, a packing of fibrous, heatand corrosion-resistant mateterial held between said rings and eecting a friction seal between said rotatable and stationary parts of said kiln, said packing material being held between said rings by means transflxing said rings and packing material and alxing same to one of the parts of the kiln, said bolts being provided with nuts which upon tightening cause the said rings to exert a pressure upon said packing material thereby to tighten the friction seal, the rotatable and stationary parts of said kiln and said rings and the packing material being disposed in such relation that the friction seal -is effected solely by means of said packing material while avoiding contact between the rotatable metal parts and the stationary metal parts. l

2. An improved seal for rotary kilns comprising a pair of flat rings encircling the rotatable part of said kiln at right angles to the axis thereof but providing clearance between the rotatable and stationary parts of said kiln, a packing of brous, heatand corrosion-resistant material held between said rings and effecting a friction sealbetween said rotatable and stationary parts of said kiln, said packing material being held between said rings by means of a plurality of threaded bolts transxing said rings and packing material and afilxing same to the stationary part of the kiln. said bolts being provided 'with nuts which upon tightening cause the said rings to exert a 'pressure upon said packing material thereby to tighten the friction seal, the rotatable and stationary parts of said kiln and said rings and the packing material being disposed in such relation that the friction seal is effected solely by means of said packing material while avoiding contact between the rotatable metal parts and the stationary metal parts.

JOHN BOARDMAN WHITNEY. 

